1. Technical Field
The present invention relates generally to chemical mechanical polishing, and more particularly, to methods of detecting diamond contamination of a polishing pad.
2. Related Art
Chemical mechanical polishing (CMP) is a method of removing layers of solid for the purpose of surface planarization and definition of metal interconnect patterns, and is a key process in back-end of line integrated circuit (IC) manufacturing. Typically, CMP is carried out using a revolving pad in a slurry to polish a semiconductor wafer. The polishing pad is made of a porous polymeric material that retains the slurry on or within the pad. During use, the polishing pad surface may become damaged, which prevents the polishing pad from providing consistent etching rates and makes the pad unusable. In order to address this situation, polishing pads are reconditioned by applying a reconditioning disk to the polishing pad that contains an abrasive in the form of diamonds. One problem with this process is that the diamonds oftentimes fall off the reconditioning disk and may become embedded in the polishing pad or otherwise contacted to the polishing pad, which results in catastrophic polishing scratches on a wafer being polished.
In view of the foregoing, there is a need in the art for methods of reconditioning a polishing pad and detecting diamond contamination thereof.